The present invention relates to an improved tact switch and particularly a tact switch adopted for use in computers, light pens, mouse devices or remote controllers.
Tact switches have been widely used in computers, light pens, mouse devices or remote controllers. A tact switch generally consists of a seat body with an open surface and a reed dome and a pushbutton located in the seat body from a lower portion to an upper portion thereof. There is a closure body mounted onto the seat body to cover all other elements. When the pushbutton receives an external force, the pushbutton presses the metallic reed dome which in turn connects the electrodes located therebelow to output a signal.
Conventional tact switches can be classified in two types. The first type has a rubber pushbutton and a reed dome made of Bexe2x80x94Cu or Pbxe2x80x94Cu. The pliable rubber pushbutton forms a soft contact with the reed dome when in use, thus may has a longer life span. However, the surface of the rubber pushbutton is prone to wear or chip off after being used for a long period of time. And the surface becomes damp and rough. Another type of tact switch has the pushbutton made from plastics. While the plastic pushbutton can maintain a smooth and tidy surface for a long period of time, its bottom end forms a hard contact with the reed dome, thus the life span of the reed dome is shorter.
In view of the aforesaid disadvantages, applicant has developed an improved tact switch which was granted in U.S. Pat. No. 6,140,596, entitled: xe2x80x9cTact Switchxe2x80x9d. That patent aims to remedy the shortcomings of conventional pushbuttons. It mainly includes a press set formed by coupling a hat body and a second elastic element. The hat body is made from plastics while the second elastic element is made from rubber. The hat body and the second elastic element are matched and coupled tightly, and has a longer durability. However, in order to form a tight coupling to prevent the hat body and the second elastic element from shaking or affecting the downward stroke when depressed, the coupling of the two must be very tight. As they are made from different materials that have different friction, coupling the two becomes difficult and troublesome. Hence although it can resolve some of the problems occurred to the conventional tact switches, there is still room for improvement, especially on the coupling and assembly of the elements.
Therefore the primary object of the invention is to resolve the aforesaid disadvantages. The invention mainly includes a hat body which has a coupling section and a directing section formed on the periphery of an opening of the hat body with an inner diameter greater than the coupling section. There is a chamfered edge formed at the juncture of the directing section and the coupling section so that a second elastic element may be inserted into the coupling section easily, and the press stroke may be maintained steadily without skew to enable electrodes to deliver signals even deformation occurred to the second elastic element when the pushbutton is depressed.